AfriGeneas Slave Research Forum

MYRICK/Georgia

I am trying to find information on my ggg grandfather, William Myrick. He was a mulatto born in 1843 or 1850 (census records I've found on him differ on his age) in Warren County, Georgia. I can trace the line from him to me perfectly, but how do I get to anyone before him? Incredibly diluted family rumor has it that his father, Joseph/Josiah (?) was a Jewish man. He had several children with a black woman, Mamie. I'm assuming she was a slave. Here's my brickwall: How do I find William's father? I've tried the 1870 census with no luck. Any suggestions on how or where to look for information?